vac arrived yesterday. assembled, fully charged both batteries.  tried out for the first time today with the floor attachment,  ran for 5 minutes. 
did a good job cleaning.  2 hours later went to use it , the battery was dead.  put in 2nd battery to vac car floor mats, 9 minutes, battery dead. 3 hours to charge.  went back to web site and  read fine print "up to 60 minutes on lowest power with no power attachments"
so you might get an hour dusting with the brush attachment but good luck trying to do the floors in 3 average size rooms before both batteries die.